Currently, if the global variable `org-html-html5-fancy' is t, some
elements of HTML export will use fancy elements even when not exporting
to HTML5 at all.

Specifically, the TITLE of a document will be wrapped in <header> tags,
even when exporting to XHTML4. I ran into this while making some epub
files and the syntax checker barked at me.

This patch fills out the check. There's growing redundancy in this file
now -- if it seems desirable to have a `org-html-html5-fancy-p' function
that encapsulates the paired checks, I'd be happy to provide that.

E